<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            color:yellow;
        }
    </style>

    <script src="./react/react.development.js"></script>
    <script src="./react/react-dom.development.js"></script>
    <script src="./react/babel.min.js"></script>
</head>
<body>
<div id="app"></div>
<script type="text/babel">

    //JSX=JS+xml、
    let app = document.querySelector('#app');
    let root = ReactDOM.createRoot(app);

    class Head extends React.Component{
        render(){
            //子组件传递到父组件
            this.props.getData('子组件的问候~~')
            return(
                <div>
                    hello world,Head{this.props.msg}
                </div>
            )
        }
    }

    class Welcome extends React.Component{
        getData = (data) => {
            console.log(data)
        }
        render(){
            return(
                <div>
                    hello world,Welcome
                    <Head msg = "子组件" getData={this.getData}></Head>
                </div>
            )
        }
    }

    let element = (<Welcome msg = "hi react class"/>)
    root.render(element);


</script>
</body>
</html>